US6700138B2 - Modular semiconductor die package and method of manufacturing thereof - Google Patents

Modular semiconductor die package and method of manufacturing thereof Download PDF

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Publication number
US6700138B2
US6700138B2 US10/081,146 US8114602A US6700138B2 US 6700138 B2 US6700138 B2 US 6700138B2 US 8114602 A US8114602 A US 8114602A US 6700138 B2 US6700138 B2 US 6700138B2
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United States
Prior art keywords
base
semiconductor die
matrix
cap
light transmissive
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US10/081,146
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English (en)
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US20030160314A1 (en
Inventor
Stanford W. Crane, Jr.
Jennifer Colegrove
Zsolt Horvath
Myoung-Soo Jeon
Joshua Nickel
Lei-Ming Yang
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Silicon Bandwidth Inc
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Silicon Bandwidth Inc
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Priority to US10/081,146 priority Critical patent/US6700138B2/en
Assigned to SILICON BANDWIDTH, INC. reassignment SILICON BANDWIDTH, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NICKEL, JOSHUA, COLEGROVE, JENNIFER, JEON, MYOUNG-SOO, YANG, LEI-MING, CRANE, JR., STANFORD W., HORVATH, ZSOLT
Priority to PCT/US2003/005534 priority patent/WO2003073474A2/en
Priority to JP2003572072A priority patent/JP2005518673A/ja
Priority to AU2003219865A priority patent/AU2003219865A1/en
Priority to US10/636,754 priority patent/US20040026757A1/en
Publication of US20030160314A1 publication Critical patent/US20030160314A1/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4292—Coupling light guides with opto-electronic elements the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
    • G02B6/4236—Fixing or mounting methods of the aligned elements
    • G02B6/4244—Mounting of the optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
    • G02B6/4236—Fixing or mounting methods of the aligned elements
    • G02B6/4245—Mounting of the opto-electronic elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4256—Details of housings
    • G02B6/4262—Details of housings characterised by the shape of the housing
    • G02B6/4263—Details of housings characterised by the shape of the housing of the transisitor outline [TO] can type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4286—Optical modules with optical power monitoring

Definitions

  • the present invention relates to semiconductor die packages and, more particularly, to modular semiconductor die packages for light emitting and/or light receiving semiconductor devices, such as laser diodes and photodetectors, and methods of manufacturing thereof.
  • Optical transmitters and optical receivers are widely used in a variety of applications including, for example, telecommunications, computing, entertainment, and medical devices.
  • Laser diodes such as Vertical Cavity Surface Emitting Lasers (VCSELs)
  • VCSELs Vertical Cavity Surface Emitting Lasers
  • TO-cans for optical applications are metal packages that typically have a windowed top, allowing light to pass through.
  • VCSELs Vertical Cavity Surface Emitting Lasers
  • TO-cans for optical applications are metal packages that typically have a windowed top, allowing light to pass through.
  • Other packages include TO-3 packages, used for higher power laser diodes.
  • Conventional TO-packages are typically costly to manufacture due in part to a lack of modularity in design, and therefore do not lend themselves to economies of scale in production.
  • AR coatings are applied to the window.
  • AR coatings may contribute significantly to the per unit cost of production, since they require additional processing steps to manufacture. Accordingly, a need exists for a cost-effective method of preventing light reflected from the window of the package from re-entering and interfering with the light emitting semiconductor device, while maintaining high coupling efficiency, low insertion loss, and without requiring the use of anti-reflective coatings on the window of the package.
  • signaling speeds may reach or exceed 10 GHz, or even 40 GHz. Consequently, there exists a need for precision modular packages with leads capable of accommodating the high speed signaling requirements associated with optical applications without generating unwanted RF interference.
  • metal TO-cans were originally intended to house transistors, not precision optical components requiring exacting alignment, metal TO-cans often do not provide the high tolerances required for automated assembly in optical applications.
  • metal TO-can packaging when metal TO-can packaging is used, manual alignment of the semiconductor device and the package is often required during production to ensure critical tolerances are maintained, making automation impractical and increasing manufacturing costs.
  • Conventional semiconductor laser packaging, such as metal TO-cans suffer from other disadvantages including high material cost and the need for special fabrication steps to integrate glass or plastic windows onto the metal can packaging.
  • a semiconductor die package includes a polymer base comprising a lower surface and an upper surface, the upper surface for mounting at least one semiconductor die.
  • a polymer cap is operatively secured over at least a portion of the upper surface of the base forming a cavity, the cap having a light transmissive member operatively positioned to allow light of predetermined wavelengths to pass between at least a portion of the upper surface of the base and the light transmissive member.
  • a plurality of conductive leads extend through the base from the lower surface of the base to the cavity.
  • a matrix of semiconductor die packages is also provided.
  • the matrix of semiconductor die packages includes a base matrix comprising a plurality of polymer bases, each base comprising a surface for mounting at least one semiconductor die.
  • the matrix of semiconductor die packages also includes a cap matrix comprising a plurality of polymer caps operatively secured over the base matrix, each base and cap combination forming a cavity, each cap having a light transmissive member operatively positioned to allow light of predetermined wavelengths to pass between the surface for mounting at least one semiconductor die of a corresponding base and the light transmissive member.
  • a plurality of conductive leads extend through each base from an outside surface of each base to the corresponding cavity formed by each cap and base combination.
  • a method of making a semiconductor die package includes forming a polymer base comprising a lower surface and an upper surface, the upper surface for mounting at least one semiconductor die; forming a polymer cap operatively secured over at least a portion of the upper surface of the base forming a cavity, the cap having a light transmissive member operatively positioned to allow light of predetermined wavelengths to pass between at least a portion of the upper surface of the base and the light transmissive member; and forming a plurality of conductive leads extending through the base from the lower surface of the base to the cavity.
  • a method of making semiconductor die packages includes forming a base matrix comprising a plurality of polymer bases, each base comprising a surface for mounting at least one semiconductor die; forming a cap matrix comprising a plurality of polymer caps operatively secured over the base matrix, each base and cap combination forming a cavity, each cap having a light transmissive member operatively positioned to allow light of predetermined wavelengths to pass between the surface for mounting at least one semiconductor die of a corresponding base and the light transmissive member; and positioning a plurality of conductive leads extending through each base from an outside surface of each base to the corresponding cavity formed by each cap and base combination.
  • FIGS. 1A-D provide an exploded view of an exemplary embodiment of a semiconductor die package according to the present invention.
  • FIG. 2 illustrates an exemplary embodiment of a base in accordance with the principles of the present invention.
  • FIG. 3 illustrates an exemplary embodiment of a base in accordance with the principles of the present invention.
  • FIG. 4 illustrates an exemplary embodiment of a base in accordance with the principles of the present invention.
  • FIG. 5 illustrates an exemplary embodiment of a base and cap in accordance with the principles of the present invention.
  • FIG. 6 illustrates a bottom view of an exemplary base in accordance with the principles of the present invention.
  • FIG. 7 illustrates an exemplary embodiment of a coaxial pin in accordance with the principles of the present invention.
  • FIG. 8 illustrates an exemplary embodiment of an assembled base and cap for surface mounting in accordance with the principles of the present invention.
  • FIG. 9 illustrates an exemplary embodiment of an assembled base and cap having a window in accordance with the principles of the present invention.
  • FIG. 10 illustrates a top view of an exemplary embodiment of a cap having a window in accordance with the principles of the present invention.
  • FIG. 11 illustrates an exemplary embodiment of a leg extension lead base in accordance with the principles of the present invention.
  • FIG. 12 illustrates an exemplary embodiment of an assembled cap, base, and leg extension lead base in accordance with the principles of the present invention.
  • FIG. 13 illustrates an exemplary embodiment of an assembled base with leg extension and cap having a tilted window in accordance with the principles of the present invention.
  • FIG. 14 illustrates an exemplary embodiment of a cap having a window and alignment projection indicator in accordance with the principles of the present invention.
  • FIG. 15 illustrates an exemplary embodiment of a cap having a window and alignment projection indicator in accordance with the principles of the present invention.
  • FIG. 16 illustrates a sectional view of an exemplary embodiment of a cap having a window in accordance with the principles of the present invention.
  • FIGS. 17A-D illustrate exemplary window embodiments in accordance with the principles of the present invention.
  • FIG. 18 illustrates a sectional view of an exemplary embodiment of a cap having a lens assembled with a base with preformed adhesive in accordance with the principles of the present invention.
  • FIG. 19 illustrates a sectional view of an exemplary embodiment of a cap having a lens assembled with a base having a leg extension in accordance with the principles of the present invention.
  • FIG. 20 illustrates an exemplary embodiment of a base with standoffs and cap having a tilted window in accordance with the principles of the present invention.
  • FIG. 21 illustrates an exemplary embodiment of a base with leg extensions and encapsulant wells surrounding the pins and cap having a tilted window in accordance with the principles of the present invention.
  • FIG. 22 illustrates an example of a signal reflected from a tilted window and received by a detector in accordance with the principles of the present invention.
  • FIG. 23 illustrates an exemplary windowed cap, and base with an emitting die and detecting die in accordance with the principles of the present invention.
  • FIG. 24 illustrates exemplary VCSEL beam divergence in accordance with the principles of the present invention.
  • FIG. 25 illustrates an exemplary optical fiber coupling in accordance with the principles of the present invention.
  • FIG. 26 illustrates an exemplary optical fiber coupling in accordance with the principles of the present invention.
  • FIG. 27 illustrates an exemplary optical fiber coupling with a lens in accordance with the principles of the present invention.
  • FIG. 28 illustrates an exemplary optical fiber coupling with a lens in accordance with the principles of the present invention.
  • FIG. 29 illustrates an exemplary matrix or array of die packages in a stacked assembly in accordance with the principles of the present invention.
  • FIG. 30 illustrates an exemplary matrix of leg extensions in accordance with the principles of the present invention.
  • FIG. 31 illustrates an exemplary matrix of bases in accordance with the principles of the present invention.
  • FIG. 32 illustrates an exemplary matrix of caps in accordance with the principles of the present invention.
  • FIG. 33 illustrates an exemplary matrix of adhesive in accordance with the principles of the present invention.
  • FIG. 34 illustrates exemplary preformed adhesive in accordance with the principles of the present invention.
  • FIGS. 1A-16 illustrate exemplary embodiments of a semiconductor die package 100 for packaging semiconductor die(s) according to the present invention.
  • FIGS. 1A-1D provide an exploded view of the semiconductor die package components shown in FIGS. 2-16.
  • semiconductor die package 100 includes a base 200 for holding one or more semiconductor dies, pins 300 retained in the base 200 for use in forming electrical connections to the semiconductor die(s), and a cap 400 secured to an upper circumferential surface 210 of the base 200 , optionally with a preformed adhesive 500 .
  • FIG. 1D depicts an optional leg extension 600 that may be securably attached to a lower surface 220 of the base 200 to enable through-hole mounting of the die package 100 on a printed circuit board.
  • the base 200 may be surface mounted directly onto a printed circuit board using any conventional surface mount technology.
  • the bodies of the base 200 , cap 400 and leg extension 600 are preferably molded of a light absorbing dark colored plastic or polymer, such as liquid crystal plastic (LCP), capable of withstanding high temperatures without exhibiting significant distortion.
  • Suitable materials include VECTRA®, which is a liquid crystal polymer plastic commercially available from Hoechst Technical Polymers, THERMALGRAPHTM available from Amoco Performance Products, Inc., COOLPOLY® D2, which is a liquid crystal polymer plastic available from Cool Polymers, Inc., and KOVAR®, which is commercially available from Carpenter Technology Corporation.
  • Cooling fins and/or heat sinks may be provided to any combinations of the base 200 , cap 400 , and leg extension 600 , for thermal management.
  • the base 200 , cap 400 , and/or leg extension 600 (if present) may be partially or completely metalized or plated with metal on one or more surfaces to provide, for example, shielding or ground planes.
  • the base 200 optionally includes a pedestal 230 having a surface 232 for semiconductor die placement.
  • the pedestal 230 may be integrally molded from the same material as used to form the base 200 .
  • the pedestal 230 may be formed of a different material from that used to form the base 200 .
  • the pedestal 230 may formed of a material having different thermal conductivity characteristics from the material used to form the base 200 .
  • the pedestal 230 may be formed of a material having a coefficient of thermal expansion that closely matches or approximates the coefficient of thermal expansion of the die(s) mounted on the pedestal so as to reduce stress on the die(s).
  • the pedestal 230 may be formed of a material having better thermal conductivity than the base 200 , thereby reducing thermal stress on the die.
  • Exemplary materials for the pedestal 230 include copper, copper-tungsten alloys, aluminum nitride, ceramic, and/or diamond, among others.
  • the pedestal 230 may be formed of a plastic having a higher thermal conductivity than the thermal conductivity of the base 200 . While FIG. 2 depicts an exemplary embodiment where the pedestal surface 232 is positioned above the top surface 240 of the base 200 , the pedestal surface 232 may alternatively be positioned flush with the top surface 240 of the base 200 , or below the top surface 240 of the base 200 .
  • the pedestal 210 may be insert-molded, adhesively secured or welded to the base 200 . Alternatively, the pedestal 210 may be secured to the base 200 in any conventional manner.
  • FIGS. 5 and 6 depict a plurality of electrically conductive pins 300 extending from the lower surface 220 through to the top surface 240 of the base 200 .
  • the pins 300 may be inserted through the base 200 after the base 200 is molded.
  • the base 200 may be molded around the pins 300 .
  • wells 250 for receiving sealant are provided around the circumference of the pin through-holes to enable hermetic sealing of the die package 100 . While FIG.
  • the wells 250 depicts the wells 250 as being formed around the circumference of the pins 300 in the top surface 240 of the base 200 , the wells 250 may also be suitably formed in the base 200 around the circumference of the pins 300 where the pins 300 extend through the lower surface 220 of the base 200 . Pins 300 will be described in greater detail in connection with FIG. 12 .
  • One or more semiconductor dies 800 may be mounted on the pedestal 230 and/or directly on a surrounding structure of the base 200 with, for example, an adhesive, such as epoxy or other suitable mounting means. If plural semiconductor dies are present, electrical connections may be formed directly between dies using any conventional interconnect method.
  • Electrically conductive material (not shown), such as bonding wire, tape automated bonding, jumpers, and/or other electrically conductive material, may be used to electrically connect the pins 300 to the semiconductor die(s) 800 . Not all of the pins 300 need to be electrically connected to the semiconductor die(s) 800 . Some of pins 300 may not be connected to any electrically conductive element on the base 200 . Alternatively or in addition, some of pins 300 may be electrically connected to electromagnetic interference (EMI) or electrostatic discharge (ESD) shielding either internal or external to the base 200 , a ground or power plane included within the base 200 , or another electrical component within the base 200 .
  • EMI electromagnetic interference
  • ESD electrostatic discharge
  • the electrically conductive pins 300 which are positioned in the base 200 , may optionally be formed with an outer conductive layer 310 coaxially arranged around a dielectric 320 and a center conductor 330 .
  • Such a coaxial arrangement couples the electromagnetic field generated by the current flowing in the center conductor 330 to a return path formed by the outer conductive layer 310 , thereby enabling high signaling rates to be achieved while reducing unwanted RF interference. It is believed that signaling rates on the order of 40 GHz may be possible, depending on, for example, the particular materials used, voltages, geometry and length of the pin.
  • Another method of achieving a coaxial pin is to metalize the pin through-holes in the base 200 and coat the pins with a dielectric before inserting them in the through-holes.
  • the center conductor 330 may have a square cross section.
  • the center conductor 330 may also have a circular cross section, a rectangular cross section or a cross section of any other suitable geometric shape.
  • the dielectric 320 and outer conductive layer 310 may have square cross sections, circular cross sections, rectangular cross sections or cross sections of any other suitable geometric shape.
  • the outer conductive layer 310 , dielectric 320 , and center conductor 330 have corresponding or identical cross sectional geometric shapes. Wire bonds forming electrical connections between coaxial pins and the semiconductor dies located in the package are preferably made using the center conductor 330 of the die pads.
  • the outer conductive layer 310 may comprise gold, aluminum, nickel, tin, silver, copper, or any other suitable conductive material, or combinations thereof.
  • the center conductor 330 may comprise gold, aluminum, nickel, tin, silver, copper, or any other suitable conductive material, or combinations thereof.
  • the dielectric 320 may comprise TEFLON® available from E. I. du Pont de Nemours and Co., however, other dielectric materials may be used as well.
  • optical alignment mark(s) or reticle(s) 295 may be provided in the top surface 240 of the base 200 to provide a reference point for precision alignment during processing steps such as positioning of the semiconductor die on the pedestal surface 232 .
  • An alignment pocket or projection reference 260 may also be provided in the base 200 , for example along a peripheral region of the base 200 , to ensure correct orientation of the package is maintained during manufacturing.
  • the alignment pocket or projection reference 260 may be semicircular in shape, as shown in FIGS. 2 and 3, angular in shape, as shown in FIG. 4, or any other suitable shape.
  • the cap 400 and optional leg extension 600 are preferably formed with corresponding alignment pockets or projection references 260 that align with the alignment pockets or projection references 260 of the cap 400 when the die package 100 is assembled.
  • FIGS. 8-10 are views of the assembled die package 100 .
  • Electrically conductive pins 300 extend from the lower surface 220 a sufficient distance to enable surface mounting of the die package 100 to a printed circuit board.
  • Stand offs 290 may optionally be provided on the lower surface 220 of the base 200 to ensure uniform spacing between the die package 100 and the printed circuit board (when the die package 100 is surface mounted), or to engage corresponding indentations 620 (shown in FIGS. 1D and 11) formed in the upper surface of the leg extension 600 (when the die package 100 is through-hole mounted).
  • the pins 300 preferably extend away from the lower surface 220 slightly less than the height of the stand offs 290 .
  • the pins 300 may also be level with the stand offs 290 or extend slightly beyond the stand offs 290 , as desired for a particular application.
  • the base 200 may be mounted using solder reflow techniques, solder balls, or any conventional mounting method.
  • a modular leg extension 600 may be provided to enable through-hole mounting of the base 200 on, for example, a printed circuit board.
  • the leg extension 600 includes a plurality of conductive pins 610 extending though the body portion of the leg extension 600 .
  • the pins 610 may be inserted through the body of the leg extension 600 after the body of the leg extension 600 is molded.
  • the body of the leg extension 600 may be molded around the pins 610 .
  • the upper surface of the leg extension 600 may include indentations 620 for engaging base stand offs 290 , ensuring positive alignment of the base 200 and leg extension 600 . As depicted in FIG.
  • the leg extension conductive pins 610 may be electrically coupled to the pins 300 extending from the lower surface 220 of the base 200 via solder reflow, solder balls, or any conventional method.
  • the body of the leg extension 600 may be physically coupled to the base 200 by soldering the leg extension pins 610 with the base pins 300 , adhesively bonding the base 200 to the leg extension 600 , welding the base 200 to the leg extension 600 , by an interference fit of the base stand offs 290 (shown on FIG. 8) with the leg extension depressions 620 (shown on FIGS. 1 D and 11 ), by clipping the base 200 to the leg extension 600 , or by any conventional method.
  • the cap 400 preferably includes an optical window 410 in a surface opposite the pedestal 230 .
  • the window 410 may be located opposite the top surface 240 of the base 200 .
  • the window 410 may or may not be transmissive for visible light.
  • the window 410 may be optically flat or it may form a lens. If a lens is used, the lens may be a ball lens, a graded index (GRIN) lens, cylindrical lens, double lens, or any other lens of a type suitable for the application. For example, if a VCSEL is provided on the pedestal 230 , a ball lens may be used.
  • GRIN graded index
  • the window 410 may be formed of glass, plastic, or any other suitable optically transmissive material.
  • a glass window 410 (or lens) is used.
  • Suitable materials for non-glass windows or lenses include optical polymers and copolymers such as PMMA (acrylic), polystyrene, polycarbonate, cyclic olifin polymer, and NAS®: Styrene and methyl methacrylate (MMA) copolymer.
  • PMMA acrylic
  • styrene polystyrene
  • polycarbonate polycarbonate
  • cyclic olifin polymer cyclic olifin polymer
  • NAS® Styrene and methyl methacrylate copolymer
  • the optical window 410 may be circular, oval, rectangular, square or any other geometric shape; however, in a preferred embodiment, the window 410 (or lens) is square to improve manufacturability and reduce waste. It has been determined that square windows 410 (or lenses) may be more readily cut and molded into the cap 400 than windows 410 (or lenses) of other shapes. It has been further determined that forming the cap 400 from a moldable non-metallic material such as plastic greatly improves manufacturability in this regard, since it is believed to be impracticable to cost-effectively mass produce non-circular windows or lenses in metal die packages, such as metal TO-cans.
  • FIGS. 17A-D illustrates exemplary window 410 dimensions that may be used to provide circular or square optically flat windows.
  • glass having a thickness of 0.4 mm+ 1 ⁇ 0.05 mm (FIGS. 17B and 17D) was found to provide excellent transmissivity characteristics for light having a wavelength of 850 nm.
  • glass having a thickness of 0.5 mm+ 1 ⁇ 0.05 mm was also found to provide satisfactory performance for light having a wavelength of 850 nm, corresponding to the operating wavelength of certain VCSELs.
  • the optical window 410 (shown in FIG. 18) may optionally be provided with an anti-reflective (AR) coating on one or both sides.
  • AR anti-reflective
  • FIG. 17A was 3.5 mm and the sides of the square window (FIG. 17C) was 3.5 mm+ 1 ⁇ 0.15 mm, although windows of other shapes and sizes may be used. For example, windows having diameters (or lengths) of 1-4 mm and thickness of 0.3-0.65 mm may be used.
  • the optical window 410 may be mounted in the cap 400 such that it lies in a plane parallel to the surface of the pedestal 232 (or the top surface of the base 240 if no pedestal is used).
  • the optical window 410 may be mounted in the cap 400 such that it lies in a plane that forms a non-zero angle with the plane parallel to the surface of the pedestal 232 (or the top surface of the base 240 if no pedestal is used).
  • This “tilt window” or “tilt lens” embodiment is particularly advantageous when light-emitting semiconductors are housed in the semiconductor package 100 , since any light reflected from the window 410 (or lens) will be directed away from the active area of the light-emitting semiconductor, preventing interference with or damage to the laser, as illustrated in FIG. 22 . In this manner the problem of reflected light re-entering the light emitting semiconductor device can be eliminated without resort to potentially costly anti-reflective (AR) coatings on the window 410 (or lens). Nonetheless, the “tilt window” or “tilt lens” embodiments may use AR coatings on the inner surface, outer surface or both surfaces of the window 410 (or lens). In a preferred embodiment, a window 410 having a trapezoidal or wedge-shaped cross section may be used to direct reflected light away from the active region of light emitting semiconductors housed in the semiconductor package 100 .
  • AR anti-reflective
  • the glass or plastic window 410 may be doped to filter certain wavelengths of light.
  • the doped window 410 (or lens) embodiments may be particularly useful when photodetectors are used to detect light having only certain wavelengths.
  • the doped window 410 (or lens) embodiments may be used with light emitting semiconductor embodiments as well.
  • the reflected portion of the beam may be directed to a detector 810 mounted within the semiconductor package to control the modulation or the laser or otherwise monitor the performance of the laser.
  • a photodetector 810 such as a photodiode
  • a detector 810 can be mounted within the die package 100 to receive the reflected portion of the light and form a feedback loop to modulate the VCSEL output.
  • the detector 810 may be located, for example, on the surface of the pedestal 232 or on the top surface 240 of the base 200 .
  • the detector 810 may comprise a PIN diode photodetector or any other suitable photodetecting device.
  • a window tilt of 8 degrees diverts the reflected beam sufficiently away from a VCSEL while providing adequate transmissivity (low insertion loss) and a reflected signal of adequate strength for the detector 810 .
  • the tilt angle is influenced by the divergence of light from the laser and the distance of the window from the laser.
  • the cap 400 may optionally be provided with a connector 420 capable of receiving an optical fiber pig tail 430 .
  • the connector 420 may be a cylindrical threaded male connector, as depicted, or any conventional type of threaded or unthreaded optical connector.
  • the connector 420 may be integrally molded with the cap 400 or the connector 420 may be separately formed and later affixed to the cap by any conventional means.
  • An optional lens 440 may be operatively positioned in the connector 420 or in the connector of the pig tail 430 .
  • a photodetector 810 shown in FIG.
  • a photo-emitting device such as a VCSEL laser diode
  • VCSEL laser diode may be positioned on the base 200 or pedestal 230 for transmitting an optical signal through the lens 440 (if present) and connector 420 to the optical fiber pig tail 430 .
  • optical coupling combinations that may be used for fiber applications include ball lens coupling, aspheric lens coupling, GRIN lens coupling, butt coupling, and lensed fiber coupling.
  • die packages 100 may preferably be assembled in layered matrix arrays to achieve economy of scale through batch processing, thereby reducing manufacturing costs.
  • a leg extension layer matrix 700 (FIG. 30) comprising a matrix of preformed leg extension subassemblies 600 may be bonded to a base layer matrix 710 (FIG. 31) comprising a matrix of pre-formed base subassemblies 200 , which may in-turn be bonded to a cap layer matrix 730 (FIG. 32) comprising a matrix of pre-formed caps 400 .
  • the layers may be assembled in any order.
  • the base layer matrix 710 may be mated with the cap layer matrix 730 before a leg extension layer matrix 700 (if present) is affixed to the base layer matrix 710 .
  • the base layer matrix 710 may be mated with a leg extension layer matrix 700 (if present) before the cap layer matrix 730 is affixed to the base layer matrix 710 .
  • Predetermined “v-groove” shaped separation lines 740 are preferably molded between individual components in each matrix layer to provide for easy separation of the die packages 100 after assembly.
  • Alignment holes 750 may optionally be formed in a margin of each layer to ensure correct alignment between layers during assembly.
  • the base layer matrix 710 (FIG. 31) and cap layer matrix 730 (FIG. 32) may be bonded together using a preformed matrix of adhesive 720 (FIG. 33 ).
  • the preformed matrix of adhesive 720 preferably comprises a plurality of epoxy rings 500 , as depicted in FIG. 34 .
  • any suitable adhesive or other bonding method may be used to affix the cap layer 730 to the base layer 710 .
  • tabs 270 used to connect adjacent bases 200 in the base layer matrix 710 during the manufacturing process may extend radially outward from the periphery of the base 200 .
  • the tabs 270 When separated from the matrix, the tabs 270 may have chamfered or beveled leading edges 280 corresponding to the predetermined “v-groove” shaped separation lines 740 formed between adjacent bases 200 in the base layer matrix 710 .
  • similar tabs 270 having chamfered or beveled leading edges 280 may also be formed in the cap 400 and optional leg extension 600 (if present).
  • the tabs 270 may be advantageously used as headers to retain completed die packages 100 during assembly of the die package 100 onto a printed circuit board.
  • the tabs 270 may also be used to mount the completed die package 100 .

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)
  • Led Device Packages (AREA)
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JP2003572072A JP2005518673A (ja) 2002-02-25 2003-02-25 モジュール型半導体ダイパッケージ及びその製造方法
AU2003219865A AU2003219865A1 (en) 2002-02-25 2003-02-25 Modular semiconductor die package and method of manufacturing thereof
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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030165167A1 (en) * 2000-03-14 2003-09-04 Sharp Kabushiki Kaisha Semiconductor laser device and wire bonding method capable of easily performing reliable wire bonding
US20030197940A1 (en) * 2002-04-18 2003-10-23 Huang Nan Tsung Lens cap for optical module
US20050018994A1 (en) * 2003-07-24 2005-01-27 Oepic, Inc. Active and passive to-can extension boards
US6849876B1 (en) * 2004-05-31 2005-02-01 Excel Cell Electronic Co., Ltd. Light emitting device
US20060019432A1 (en) * 2003-10-31 2006-01-26 Sharp Kabushiki Kaisha Method for manufacturing semiconductor device having shielding case, electronic equipment using the semiconductor device, and shielding case attaching method
US20070228265A1 (en) * 2006-03-31 2007-10-04 Ramachandran Premkumar S Optical encoder apparatus for removable connection with a printed circuit board and methods of assembling optical encoder apparatus
US20080218051A1 (en) * 2007-03-07 2008-09-11 Everlight Electronics Co., Ltd. Socket LED device
US20090080197A1 (en) * 2006-03-21 2009-03-26 Koninklijke Philips Electronics N.V. Light emitting diode module and method for the manufacturing of such an led module
US20120140306A1 (en) * 2010-11-29 2012-06-07 Stefan Pinter Cover device for a micro-optomechanical component, and manufacturing method for such a cover device
DE102011012511A1 (de) * 2011-02-25 2012-08-30 Limo Patentverwaltung Gmbh & Co. Kg Vorrichtung zur Überlagerung von Laserstrahlen einer Mehrzahl von Laserlichtquellen in einer Arbeitsebene
US20130258474A1 (en) * 2012-04-03 2013-10-03 Cheng-Ta Chen Optoelectronic device with improved lens cap
US20150130040A1 (en) * 2011-04-01 2015-05-14 Schlumberger Technology Corporation High Density Microelectronics Packaging
US20150147034A1 (en) * 2013-11-27 2015-05-28 Texas Instruments Incorporated Optical Connector
US20210198102A1 (en) * 2018-07-11 2021-07-01 Robert Bosch Gmbh Production method for a micromechanical device having inclined optical windows, and micromechanical device having inclined optical windows

Families Citing this family (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004288674A (ja) * 2003-03-19 2004-10-14 Fuji Xerox Co Ltd 面発光型半導体レーザおよびそれを用いた光通信システム
US7010013B2 (en) * 2003-05-02 2006-03-07 Applied Optoelectronics, Inc. Assembly with tapered, threaded ferrule housing for improved alignment of fiber with laser
DE102004004779B4 (de) * 2004-01-30 2015-09-03 Osram Opto Semiconductors Gmbh Leuchtdioden-Beleuchtungsmodul mit optischer Einrichtung zur Strahlformung
US7256922B2 (en) * 2004-07-02 2007-08-14 Idc, Llc Interferometric modulators with thin film transistors
DE102004051379A1 (de) * 2004-08-23 2006-03-23 Osram Opto Semiconductors Gmbh Vorrichtung für ein optoelektronisches Bauteil und Bauelement mit einem optoelektronischen Bauteil und einer Vorrichtung
US7843410B2 (en) 2004-09-27 2010-11-30 Qualcomm Mems Technologies, Inc. Method and device for electrically programmable display
US8310441B2 (en) 2004-09-27 2012-11-13 Qualcomm Mems Technologies, Inc. Method and system for writing data to MEMS display elements
US7170376B2 (en) * 2004-12-09 2007-01-30 Eaton Corporation Electrical switching apparatus including a housing and a trip circuit forming a composite structure
US20060246615A1 (en) * 2005-04-27 2006-11-02 Unity Opto Technology Co., Ltd. Method of manufacturing vertical cavity surface emitting laser
KR20080027236A (ko) 2005-05-05 2008-03-26 콸콤 인코포레이티드 다이나믹 드라이버 ｉｃ 및 디스플레이 패널 구성
US7358836B2 (en) * 2006-03-29 2008-04-15 Eaton Corporation Shield, and printed circuit board and electrical apparatus employing the same
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US8084731B2 (en) * 2006-09-09 2011-12-27 Johnson Douglas M Sensor system for liquid detection with lens component having an apex
US7556981B2 (en) 2006-12-29 2009-07-07 Qualcomm Mems Technologies, Inc. Switches for shorting during MEMS etch release
US7957589B2 (en) * 2007-01-25 2011-06-07 Qualcomm Mems Technologies, Inc. Arbitrary power function using logarithm lookup table
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DE102009005547A1 (de) * 2009-01-20 2010-07-29 R. Stahl Schaltgeräte GmbH Gekapselte Leuchtdiodenanordnung
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5323025A (en) * 1989-05-18 1994-06-21 Murata Mfg. Co., Ltd. Pyroelectric IR-sensor having a low thermal conductive ceramic substrate
US5953355A (en) * 1997-04-02 1999-09-14 Motorola, Inc. Semiconductor laser package with power monitoring system
US6541800B2 (en) * 2001-02-22 2003-04-01 Weldon Technologies, Inc. High power LED

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5825054A (en) * 1995-12-29 1998-10-20 Industrial Technology Research Institute Plastic-molded apparatus of a semiconductor laser
WO1997032344A1 (en) * 1996-02-28 1997-09-04 The Whitaker Corporation Packaging for optoelectronic device
US5692083A (en) * 1996-03-13 1997-11-25 The Whitaker Corporation In-line unitary optical device mount and package therefor
CA2367362C (en) * 1999-03-19 2004-11-09 Cielo Communications, Inc. Vcsel power monitoring system using plastic encapsulation techniques
US6243508B1 (en) * 1999-06-01 2001-06-05 Picolight Incorporated Electro-opto-mechanical assembly for coupling a light source or receiver to an optical waveguide
US6302596B1 (en) * 1999-07-07 2001-10-16 International Business Machines Corporation Small form factor optoelectronic transceivers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5323025A (en) * 1989-05-18 1994-06-21 Murata Mfg. Co., Ltd. Pyroelectric IR-sensor having a low thermal conductive ceramic substrate
US5953355A (en) * 1997-04-02 1999-09-14 Motorola, Inc. Semiconductor laser package with power monitoring system
US6541800B2 (en) * 2001-02-22 2003-04-01 Weldon Technologies, Inc. High power LED

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6784464B2 (en) * 2000-03-14 2004-08-31 Sharp Kabushiki Kaisha Semiconductor laser device and wire bonding method capable of easily performing reliable wire bonding
US20030165167A1 (en) * 2000-03-14 2003-09-04 Sharp Kabushiki Kaisha Semiconductor laser device and wire bonding method capable of easily performing reliable wire bonding
US20030197940A1 (en) * 2002-04-18 2003-10-23 Huang Nan Tsung Lens cap for optical module
US20050018994A1 (en) * 2003-07-24 2005-01-27 Oepic, Inc. Active and passive to-can extension boards
US7285439B2 (en) * 2003-10-31 2007-10-23 Sharp Kabushiki Kaisha Method for manufacturing semiconductor device having shielding case, electronic equipment using the semiconductor device, and shielding case attaching method
US20060019432A1 (en) * 2003-10-31 2006-01-26 Sharp Kabushiki Kaisha Method for manufacturing semiconductor device having shielding case, electronic equipment using the semiconductor device, and shielding case attaching method
US6849876B1 (en) * 2004-05-31 2005-02-01 Excel Cell Electronic Co., Ltd. Light emitting device
US20090080197A1 (en) * 2006-03-21 2009-03-26 Koninklijke Philips Electronics N.V. Light emitting diode module and method for the manufacturing of such an led module
US7439487B2 (en) 2006-03-31 2008-10-21 Avago Technologies General Ip (Singapore) Pte Ltd Optical encoder apparatus for removable connection with a printed circuit board and methods of assembling optical encoder apparatus.
US20070228265A1 (en) * 2006-03-31 2007-10-04 Ramachandran Premkumar S Optical encoder apparatus for removable connection with a printed circuit board and methods of assembling optical encoder apparatus
US20090127446A1 (en) * 2006-03-31 2009-05-21 Avago Technologies General Ip (Singapore) Pte. Ltd Optical Encoder Apparatus for Removable Connection with Printed Circuit Board and Methods of Assembling Optical Encoder
US7667189B2 (en) 2006-03-31 2010-02-23 Avago Technologies General Ip (Singapore) Pte. Ltd. Optical encoder apparatus for removable connection with printed circuit board and methods of assembling optical encoder
US20080218051A1 (en) * 2007-03-07 2008-09-11 Everlight Electronics Co., Ltd. Socket LED device
US8550639B2 (en) * 2010-11-29 2013-10-08 Robert Bosch Gmbh Cover device for a micro-optomechanical component, and manufacturing method for such a cover device
US20120140306A1 (en) * 2010-11-29 2012-06-07 Stefan Pinter Cover device for a micro-optomechanical component, and manufacturing method for such a cover device
DE102011012511A1 (de) * 2011-02-25 2012-08-30 Limo Patentverwaltung Gmbh & Co. Kg Vorrichtung zur Überlagerung von Laserstrahlen einer Mehrzahl von Laserlichtquellen in einer Arbeitsebene
US20150130040A1 (en) * 2011-04-01 2015-05-14 Schlumberger Technology Corporation High Density Microelectronics Packaging
US9431375B2 (en) * 2011-04-01 2016-08-30 Schlumberger Technology Corporation High density microelectronics packaging
US20130258474A1 (en) * 2012-04-03 2013-10-03 Cheng-Ta Chen Optoelectronic device with improved lens cap
US20150147034A1 (en) * 2013-11-27 2015-05-28 Texas Instruments Incorporated Optical Connector
US20210198102A1 (en) * 2018-07-11 2021-07-01 Robert Bosch Gmbh Production method for a micromechanical device having inclined optical windows, and micromechanical device having inclined optical windows
US11479461B2 (en) * 2018-07-11 2022-10-25 Robert Bosch Gmbh Production method for a micromechanical device having inclined optical windows, and micromechanical device having inclined optical windows

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US20030160314A1 (en) 2003-08-28
AU2003219865A1 (en) 2003-09-09
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WO2003073474A8 (en) 2004-10-14
US20040026757A1 (en) 2004-02-12
AU2003219865A8 (en) 2003-09-09
WO2003073474A2 (en) 2003-09-04

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